Polysulfated aliphatic or cycloaliphatic alcohols as antifoggants



United States Patent 3,475,175 POLYSULFATED ALIPHATIC 0R CYCLOALI- PHATIC ALCOHOLS AS ANTIFOGGANTS James R. King, Jr., Webster, and Thomas E. Whiteley and Louis M. Minsk, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Aug. 19, 1966, Ser. No. 573,479 lint. Cl. G03c J/34 US. Cl. 96-109 18 Claims ABSTRACT OF THE DISCLOSURE Photographic compositions and photographic elements comprising a silver halide emulsion are stabilized against fog with an effective amount of a water-soluble salt of a polysulfated, aliphatic or cycloaliphatic alcohol containing from 2 to 12 carbon atoms.

This invention relates to new and improved antifoggants and stabilizers for photographic elements and to photographic silver halide emulsions containing said antifoggants and stabilizers therein. More particularly, this invention relates to photographic elements and silver halide emulsions containing a salt of a polysulfated, aliphatic or cycloaliphatic alcohol.

During development of a silver halide emulsion, small amounts of silver halide are reduced to metallic silver regardless of whether or not they have been exposed. This reduction of silver ion produces a background fog which is more specifically referred to as chemical fog.

Chemical fog, apparent in most silver halide systems, has been reduced by prior art methods of processing exposed silver halide material in the presence of compounds which restrict development of unexposed silver halide. Such compounds can be incorporated in the silver halide emulsion or in the processing solutions for developing such silver halide emulsions. Compounds which have been found to have a chemical fog inhibiting effect on emulsions which have been subjected to high temperature and high humidity conditions are referred to as emulsion stabilizers. On the other hand, compounds which have been found to have chemical fog inhibiting effects on emulsions which have not been exposed to adverse storage conditions are referred to as antifoggants. Although a large number of emulsion stabilizers and antifoggants have been used in the prior art, many of these compounds cause undesirable losses in emulsion speed and'contrast; others lack adequate compatibility with emulsion gelatin, and still others must be employed in inordinantly high concentrations.

Accordingly, it is an object of our invention to provide novel antifoggants and stabilizers for photographic silver halide emulsions.

A further object is to provide a photographic element containing a fog inhibiting compound either in the photographic emulsion or in a layer contiguous thereto. 7

Still another object is to provide novel antifoggants for photographic silver halide emulsions which have little or no effect on the contrast of the processed material.

Still another object is to provide silver halide emulsion stabilizers which maintain sensitivity and fog levels of silver halide emulsions at or near the initial optimum values under conditions of high temperature and humidity.

Other objects will become apparent hereinafter.

The above objects are accomplished by incorporating into the silver halide emulsion of a photographic element or in a layer contiguous to the silver halide emulsion, a fog-stabilizing amount of a water-soluble salt of a p'olysulfated, aliphatic or cycloaliphatic alcohol containing from 2 to 12 carbon atoms. In general, ammonium and alkali metal salts such as sodium, potassium or lithium salts are preferred. Mixtures of alkali metal salts and mixtures of ammonium and alkali metal salts are also quite useful. The salt of the polysulfated, aliphatic or cycloaliphatic alcohol may have hydroxyl or alkyl groups attached thereto and may also contain an oxa group. The ratio of monohydric sulfate groups to the number of carbon atoms in the salt may vary from 1:1 to about 1:3, but is preferably from 1:1 to about 1:2. In the preferred embodiment of the present invention, compounds having from 2 to 6 carbon atoms have been highly effective in inhibiting chemical fog in silver halide emulsions.

Another way to describe the polysulfated salts of the invention is the following formula:

Where R is an aliphatic or cycloaliphatic alcohol containing from 2 to 12 carbon atoms, M is an inorganic cation and n is at least 2. Of the inorganic cations that M can represent, ammonium and alkali metals such as sodium, potassium or lithium are preferred. Mixtures of alkali metals and mixtures of alkali metals with ammonium are also quite useful.

The polysulfates of the invention may be prepared by the monohydric sulfation of saturated polyhydroxy compounds such as, for example, the following:

Ethylene glycol Diethylene glycol Propylene glycol Glycerol Pentaerythritol Dipentaerythritol 2-methyl-2,4-pentanediol 1,2,6-hexanetriol 2,2,5,5-tetramethyl-l,3,4,6-hexanetetrol Mannitol Dulcitol Mannoheptitol Inositol Sorbitol 2,7-dimethyloctanediol 1,2,4-decanetriol 1,4-cyclohexanediol Cyclohexanedimethanol, and 1,2,4,S-tetrahydroxycyclohexane A convenient method for preparing the compounds of the invention is to heat the polyhydroxy compound with an excess of sulfamic acid in the presence of a solvent, such as hexamethylphosphorictriamide or N,N-dimethylformamide. The product can then be dissolved in water and the pH adjusted for subsequent use with an appropriate base.

The term polysulfate as used in this invention refers to compounds containing a plurality of monohydric sulfate groups, -OSO M, where M is an inorganic cation, preferably ammonium or alkali metal or mixtures thereof. Typical examples of polysulfated compounds embraced by our invention are:

Ethylene clisulfate ammonium salt Ethylene disulfate ammonium-sodium salt Diethylene disul-fate ammonium salt Glycerol trisulfate ammonium salt Glycerol trisulfate potassium salt Propylene disulfate sodium salt Propylene disulfate ammonium salt 2-methyl-2,4-pentanediol disulfate ammonium salt Pentaerythritol tetrasulfate ammonium salt Pentaerythritol disulfate ammonium salt Dipentaerythritol hexasulfate ammonium-sodium salt Mannitol hexasulfate ammonium salt Mannitol tetrasulfate ammonium salt Dulcitol hexasulfate ammonium salt Dulcitol tetrasulfate ammonium-sodium salt Mannoheptitol heptasulfate ammonium salt Mannoheptitol pentasulfate ammonium salt 1,2,6-hexanetriol trisulfate ammonium salt 1,4-cyclohexanediol disulfate ammonium salt 1,2,4,S-tetrahydroxycyclohexane tetrasulfate ammonium sodium salt, and

1,2,4,S-tetrahydroxycyclohexane tetrasulfate ammonium salt The compounds of this invention may be used in any amount which will stabilize the silver halide emulsion against fog. In general, a concentration of the salt in an amount of about 5 g. to about 3 g. per mole of silver in the silver halide emulsion is useful. A preferred concentration for the salt is from about 15 g. to about 30 g. per mole of silver in the silver halide emulsion.

In addition to their excellent fog stabilizing properties, the compounds of the invention tend to increase the speed of the photographic emulsions in which they are incorporated. The increased speed is obtained without adversely afiecting other sensitometric properties such as contrast.

The invention can be further illustrated by the following examples or preferred embodiments thereof; although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated.

The preparation of the fog inhibiting agents in accordance with the invention is exemplified in Examples 1-5.

EXAMPLE 1 Preparation of ethylene disulfate ammonium salt Into a 300 ml. three-neck flask, fitted with a magnetic stirrer, a condenser, a thermometer, and a steam bath, were placed 6.2 g. (0.1 mole) of ethylene glycol, 19.4 g. (0.2 mole) of sulfamic acid and 200 ml. of hexamethylphosphorictriamide. The mixture was stirred and heated to a homogeneous solution at 100 C. The temperature peaked at 105 C. as the reaction solution became very hazy. Heating was continued for one-half hour, and then the solution was filtered through a Buchner funnel. The clear filtrate was poured into two liters of ethyl acetate. The precipitate was filtered out on a Buchner funnel and washed with 500 ml. of ethyl ether. The product was dried under reduced pressure at 35-40 C. Yield, 20 g.

Analysis.-Calcd. for C H N O S C, 9.4; H, 4.7; N, 10.9; S, 25.0. Found: C, 10.1; H, 4.7; N, 10.7; S, 23.8.

A solution of 18.6 g. of the dried product in 40 g. of distilled water was prepared and adjusted to pH 7.1 with ten percent ammonium hydroxide. The resulting solution weighed 53.3 g. and contained 31.3 percent solids.

EXAMPLE 2 Preparation of glycerol trisulfate ammonium salt Into a 300 m1. three-neck flask, fitted with a magnetic stirrer, a condenser, a thermometer and a steam bath, were placed 9.2 g. (0.1 mole) of glycerol, 150 ml. of hexamethylphosphorictriamide, and 29.1 g. (0.3 mole) of sulfamic acid. The reaction mixture was stirred and heated to a homogeneous solution as the temperature rose and peaked'at 113 C. Heating was continued for one-half hour as the temperatur dropped to 100 C. The hot hazy reaction solution was filtered through a Buchner funnel with suction.

The clear filtrate was poured into two liters of stirred ethyl acetate. The precipitate was filtered out on a Buchner funnel, washed with 500 ml. of anhydrous ethyl ether, and dried under reduced pressure at 35-40 C. Yield, 31.0 g.

Analysis.Calcd. for C H N O S C, 9.4; H, 4.5; N, 11.0; S, 25.0. Found: C, 11.2; H, 4.3; N, 10.2; S, 23.8.

A solution of 29.9 g. of the dried product in 75 g. of distilled water was prepared and adjusted to pH 7.1 with ten percent ammonium hydroxide. The resulting solution weighed 104 g. and contained 24.0 percent solids.

EXAMPLE 3 Preparation of polysulfated dulcitol ammonium salt Into a 300 m1. three-neck flask, fitted with a magnetic stirrer, a condenser, a thermometer, and a steam bath, were placed 200 ml. of N,N-dimethylformamide, 9.1 g. (0.05 mole) of ducitol and 29.1 g. (0.30 mole) of sulfamic acid. The reaction mixture was heated to a homogeneous solution at -86 C. Heating was continued and the temperature peaked at 102 C. as the reaction solution became very hazy. The reaction solution was heated at -100 C. for one-half hour, and filtered with suction through a Buchner funnel to yield a clear filtrate.

The filtrate was poured into three liters of stirred methanol and the white precipitate was filtered out on a Buchner funnel and washed with 500 ml. of methanol. The product was dried under reduced pressure at 35-40 C. Yield, 22.8 g.

Analysis.Calcd. for C H N O S C, 9.5; H, 4.2; N, 11.0; S, 25.2. Found: C, 14.3; H, 5.0; N, 11.8; S, 22.1. A solution of 21.3 g. of the dried product in 60 g. of distilled water was prepared and adjusted to pH 7.1 with ten percent ammonium hydroxide. The resulting solution weighed 77.2 g. and contained 22.6 percent solids.

EXAMPLE 4 Preparation of polysulfated mannitol ammonium salt Into a 300 m1. three-neck flask, fitted with a magnetic stirrer, a condenser, a thermometer, and a steam bath, were placed 200 ml. of N,N-dimethylformamide, 9.1 g. (0.05 mole) of mannitol, and 29.1 g. (0.30 mole) of sulfamic acid. The reaction mixture was stirred and heated to a homogeneous solution at 74 C. Heating was continued as the solution became hazy and the temperature peaked at 101 C. The hazy solution was then stirred at 95-100 C. for one-half hour and filtered hot through a Buchner funnel.

The clear filtrate was poured into three liters of stirred methanol and the precipitate was filtered out with suction on a Buchner funnel and washed with 500 ml. of methanol. The product was dried under reduced pressure at 35-40 C. Yield, 21 g.

Analysis.--Calcd. fOl' C5H3ZNQOZ4SBZ C, 9.5; H, 4.2; N, 11.0; S, 25.2. Found: C, 14.8; H, 5.3; N, 11.6; S, 22.1.

A solution of 19.1 g. of the dried product in 60 ml. of distilled water was prepared and adjusted to pH 7.1 with ten percent ammonium hydroxide. The resulting solution contained 28.1 percent solids.

EXAMPLE 5 Preparation of penetaerythritol tetrasulfate ammonium salt Into a 300 ml. three-neck flask, fitted with a condenser, a magnetic stirrer, a thermometer, and a heating mantle were placed 13.6 g. (0.1 mole) of pentaerythritol, 48.5 g. (0.5 mole) of sulfamic acid and 200 ml. of N,N- dimethylformamide. The reaction mixture was heated to a homogeneous solution at 75 C. Heating was continued and a white crystalline precipitate separated out at C. The

heat was removed and the mixture stirred at ambient temperature for ten mintues.

The precipitate was filtered from the hot N,N-dimethylformamide on a Buchner funnel and washed with 200 ml. of acetone. The crystals were dried under reduced pressure at 45 C. Yield, 39.9 g.

Analysis.Calcd. for ammonium salt C H N O S C, 11.4; H, 4.6; N, 10.7; S, 24.4. Found: C, 12.1; H, 5.1; N, 10.9; S, 23.8.

A solution of 15 g. of the dried crystals in 50 ml. of distilled water was prepared and adjusted to pH 0.5 by slurrying with Amberlite resin IR 120 (an ion exchange resin comprising polystyrenesulfonic acid manufactured by the Rohm and Haas Company). The resin was filtered of the invention may be of the surface-sensitive or internally sensitive type. The emulsions may also contain speed-increasing addenda such as quaternary ammonium salts, polyethylene glycols, or thioether sensitizers.

The emulsions of the invention may also contain conotf by gravity and the filtrate was adjusted to a pH of 5 ventional addenda such as gelatin plasticizers, hardeners 7.1 with ten percent sodium hydroxide. The resulting solu and coating aids. These emulsions may be useful in X-ray tion weighed 55.9 g. and contained 19.3 percent solids. and other non-optically sensitized emulsions, and may also EXAMPLE 6 be used in orthochromatic, panchromatic and infrared 10 sensit ve emulsions. The addenda may be added to the Several dlfiefent Compounds of the IIIVeIltlOn were emulslon before or after sensitizing dyes, if any, are used. added to Separate Portions of a high Speed Silver bIOmO- Various silver salts may be used as the sensitive salt, such iodide emulsion- Each emulsion Sample Was Coated 011 a as silver bromide, silver iodide, silver chloride, or mixed cellulose acetate film pp at a Coverage of gof silver halides such as silver chlorobromide or silver bromo- Silver and 1040 of gelatin P Squam foot- A Sample iodide. The emulsions may be used in photographic eleof each film Coating was exposed on an Eastman 1B merits intended for color photography, and thus may consensitometel', Processed five minutes in a Standard tain color-forming couplers, or used as emulsions to be developer (Kodak Developer fixed, Washed and developed by solutions containing couplers or other colordried. The photographic results obtained from these tests generating materials, or emulsions of the mixed-packet are listed in Table I. type, as disclosed by Godowsky, US. Patent No. 2,698,794,

TABLE I 2-week Incubation at 120 F. and 50% Relative (3011c. Fresh Humidity glindiia Rel. Rel. Compound Ag Speed Gamma Fog Speed Gamma Fog Ethylene disultate ammonium salt 0 105 1.35 0.12 87 1.18 0.17 Glycerol tris'ultate ammonium salt... 30 105 1.33 0.10 74 1.25 0.10 Duleitol hexasnlfate ammonium salt. 30 91 1.28 0.11 80 1.20 0.15 Mannitol hexasulfate ammonium salt. 30 97 1.32 0.10 78 1.20 0.14 Control 100 1. 32 0.14 0.75 1.01 Pentaerythritol tetrasulfate ammonium salt 95 1.32 0.09 68 1.20 0.09 Control 100 1.23 0.15 22 0.73 0.01

The results in the above table show that the compounds or emulsions of the mixed-grain type, such as disclosed of the invention prevent the growth of incubation fog by Carroll et al., US. Patent No. 2,592,243. when incorporated in photographic emulsions. Further it 35 The emulsions obtained in accordance with out invenis seen that these compounds often serve advantageously tion may be used in diffusion transfer processes which to increase the emulsion speed while maintaining a stable utilize the undeveloped silver halide in non-image areas value for gamma. of the negative to form a positive by dissolving the un- The fog-stabilizing effect of the compounds of the indeveloped silver halide and precipitating it on a silver vention is surprising and would not have been expected layer in close proximity to the original silver halide emulin view of the fact that mono-sulfated alcohols such as sion layer. The emulsions may also be used in diffusion Triton 770, and aqueous solution of a sodium salt of an transfer color processes which utilize a diffusion transalkylarylpolyether sulfate made by the Rohm and Haas fer of an imagewise distribution of developer, coupler or Company, and sodium lauryl sulfate, do not control fog dye, from a light-sensitive layer to a second layer, while and are essentially inert when incorporated in a photothe two layers are in close proximity to one another. graphic emulsion. The following example illustrates this -A wide variety of emulsion vehicles and dispersing feature. agents for silver halide grains may be employed singly EXAMPLE 7 or in combination with each other, for example, gelatin, Com arative test colloidal albumen, cellulose derivatives and synthetic p resms, such as polyvinyl compounds. Examples of typical Samples of Triton 770 and DuP01101 a Sodium colloids which may be used are poly(vinyl alcohol), hylauryl sulfate made y the D11 POII'E p y were drolyzed poly(vinyl acetate), hydrolyzed cellulose ester, corporated in Separate PortionS 0f Photographic emulsion water-soluble ethanolamine cellulose acetate, polyacryland processed as in Example 6. The results are contained amide, copolymers having a combined acrylamide conin Table II below. tent of 3-60 percent, copolymers of alkyl acrylate and TABLE H acrylic acid, a vinyl alcohol copolymer containing urethane carboxylic acid groups or containing cyano-acetyl W33 $33 239}: at groups, or polymeric material which results from polym- Cone. Fresh Relative Humidity erizing a protein or saturated acrylated protein with a 2 5- Re] REL monomer having a vinyl group such as disclosed by 111- Compound Ag Speed Gamma Fog Speed Gamma Fog ingsworth, U.S. Patent 2,852,382. Such polymeric addenda Triton 770 12 100 L23 0' 10 (1) (1) (1) may be employed as latices of hydrosols in the preparap 12 83 35 014 tron of the photographic emulsions of our invention. Comm 100 The antifogging agents of our invention may be in- After two weeks incubation, the Sensitometric strips were corporated to advantage during manufacture in silver and it was not PSsib1e to diistinguish halide emulsions representing the variations described tween the individual steps.

above. Moreover, fog control in b1nderless silver halide Photographic emulsions containing the antifogging and films prepared by vapor deposition of silver halide on a stabilizing agents of the present invention may be sensisuitable support may be achieved by coating the antitized using any of the well-known techniques in emulsion fogging agents of the invention over the vapor-deposited making, for example, by digesting with naturally active layer of silver halide. gelatin or various sulfur compounds and/or gold com- Although the invention has been described in considerpounds. The emulsions may be sensitized with salts of able detail with reference to certain embodiments therenoble metals of Group VIII of the periodic table which of, it will be understood that variations and modifications have an atomic weight greater than 100. The emulsion can be effected without departing from the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A composition comprising a photographic silver halide emulsion containing a fog-stabilizing amount of a water-soluble sale having the formula:

where 'R is a residue of a polyhydroxy aliphatic or cycloaliphatic alcohol containing from 2 to 12 carbon atoms and having at least two of said hydroxy groups each replaced by a monohydric sulfate group, M is an inorganic cation and n is at least 2.

2. The composition of claim 1 wherein said salt is present in an amount of about to about 30 grams per mole of silver in said silver halide emulsion.

3. The composition of claim 1 wherein each M is ammonium or an alkali metal.

4. The composition of claim 1 wherein said salt is ethylene disulfate ammonium salt.

5. The composition of claim 1 wherein said salt is glycerol trisulfate ammonium salt.

6. The composition of claim 1 wherein said salt is dulcitol hexasulfate ammonium salt.

7. The composition of claim 1 wherein said salt is mannitol hexasulfate ammonium salt.

8. The composition of claim 1 wherein said salt is pentaerythritol tetrasulfate ammonium-sodium salt.

9. A photographic element comprising a support coated with a silver halide emulsion, said element containing a for-stabilizing amount of a water-soluble salt having the following formula:

where R is a residue of a polyhydroxy aliphatic or cycloaliphatic alcohol containing from 2 to 12 carbon atoms and having at least two of said hydroxy groups each replaced by a monohydric sulfate group, M is an inorganic cation and n is at least 2.

10. The photographic element of claim 9 wherein said salt is present in an amount of about 5 to about 30 grams per mole of silver in said silver halide emulsion.

11. The protographic element of claim 9 wherein each M is ammonium or an alkali metal.

12. The photographic element of claim 9 wherein said salt is ethylene disulfate ammonium salt.

13. The photographic element of claim 9 wherein said salt is glycerol trisulfate ammonium salt.

14. The photographic element of claim 9 wherein said salt is dulcitol hexasulfate ammonium salt.

15. The photographic element of claim 9 wherein said salt is mannitol hexasulfate ammonium salt.

16. The photographic element of claim 9 wherein said salt is pentaerythritol tetrasulfate ammonium-sodium salt.

17. The photographic element of claim 9 wherein said salt is present in said silver halide emulsion.

18. The photographic element of claim 9 wherein said salt is present in a layer contiguous to said silver halide emulsion.

References Cited UNITED STATES PATENTS 3,392,023 7/1968 Burness 96-109 X 3,396,028 8/1968 Humphlett 96-109.

NORMAN G. TORCHIN, Primary Examiner R. E. FIGHTER, Assistant Examiner w UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 7 I Dated at L' (Inf-11' It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

SIGNED AND SEALED MAY 1 21970 Edward M. fi Commissioner of Patents Aticsting Officer 

